21248671 has 6 divisors (see below), whose sum is σ = 21957216. Its totient is φ = 20562300.

The previous prime is 21248663. The next prime is 21248687. The reversal of 21248671 is 17684212.

It is not a de Polignac number, because 21248671 - 2³ = 21248663 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21248641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10095 + ... + 12016.

It is an arithmetic number, because the mean of its divisors is an integer number (3659536).

Almost surely, 2^21248671 is an apocalyptic number.

21248671 is a deficient number, since it is larger than the sum of its proper divisors (708545).

21248671 is an equidigital number, since it uses as much as digits as its factorization.

21248671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22173 (or 22142 counting only the distinct ones).

The product of its digits is 5376, while the sum is 31.

The square root of 21248671 is about 4609.6280761033. The cubic root of 21248671 is about 276.9771384383.

The spelling of 21248671 in words is "twenty-one million, two hundred forty-eight thousand, six hundred seventy-one".